JP2005289551A - Polyp-shaped single cable type grab bucket - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyp-shaped single cable type crab bucket capable of performing loading/unloading operations safely and efficiently even when a load is pinched between nail-shaped shells. <P>SOLUTION: A hydraulic cylinder 6 is used for a relative operation control mechanism between middle lower frames of the polyp-shaped grab bucket of the single cable type. A hydraulic cylinder control means for controlling operation of the hydraulic cylinder is provided with a hydraulic passage 30 allowing intercommunication between upper and lower oil pressure chambers of the hydraulic cylinder wherein a flow limiting valve mechanism to make only a small quantity of operating oil flow and a normal operation valve mechanism to make a large quantity of the operating oil flow are provided in parallel, and a hydraulic sensor 31 for detecting oil pressure of the hydraulic passage 30. Only a small quantity of the operating oil is allowed to flow through the flow limiting valve mechanism when the pressure in the hydraulic passage 30 is equal to or more than a prescribed value at the time of grab releasing operation, and a large quantity of the operating oil is allowed to flow through the normal operation valve mechanism when the pressure in the hydraulic passage 30 is equal to or less than the prescribed value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polyp type single rope type grab bucket that is mainly suspended on a crane and used for cargo handling work of loose objects.

  Conventionally, a polyp type single-line grab bucket operated by a crane is used for cargo handling such as scrap, large block ore, rock, sticky material, bulky garbage, and wood chips that are difficult to grasp.

  As shown in FIGS. 7 to 8, for example, this type of conventional polyp type single rope type grab bucket has six petals arranged in a radial direction with its upper end pivotally supported by the lower frame 3. The grab 1 is constituted by the claw-shaped shells 2, 2..., And when the grab 1 is closed, that is, when the side edges of the respective claw-shaped shells 2 are joined, the grip with the bottom surface closed inside. A space is formed.

  An intermediate movable frame 7 is provided on the lower frame 3, and an upper frame 5 is provided thereon. The intermediate movable frame 7 is installed so as to be able to slide up and down along a guide shaft 50 projecting upward from the lower frame 3, and constitutes a middle-lower frame relative motion control mechanism projecting upward from the lower frame 3. It is locked to the opening / closing claw 51. The opening / closing claw 51 is opened and closed by remote operation.

  A suspension arm 4 is interposed between the upper frame 5 and the back surface of each claw-type shell 2, and each claw-type shell 2 is operated in the opening direction by opening a space between the upper and lower frames 5, 3. By narrowing the interval, the claw-shaped shell 2 is moved in the closing direction, that is, in the gripping direction.

  In the upper frame 5 and the intermediate movable frame 7, a wire rope 8 for lifting operation is hung between pulleys 17 and 18 provided in each. One end of the wire rope 8 is fixed to the intermediate movable frame 7, the other end wound around the pulleys 17 and 18 of both frames 5 and 7 is led out to the upper frame 5, and is lifted by a crane via a lifting tool. It is supposed to be.

  As shown in FIG. 7, the operation of the polyp type single rope type grab bucket constructed as described above is performed by lowering the intermediate movable frame 7 by lowering the wire rope 8 while the lower end of the grab is grounded. It is engaged with the opening / closing claw 51 of the frame 3. By lifting the wire rope 8 in this state, the space between the upper frame 5 and the intermediate movable frame 7 is shortened by the wire rope 8, and the lower frame 3 is moved together with the intermediate movable frame 7, thereby closing the claw-shaped shell 2. The cargo is held in the grab 1 and lifted.

  In this state, by moving to the desired cargo drop position and opening the opening / closing claw 51, the engaged state of the lower frame 3 with respect to the intermediate movable frame 7 is released, and the lower frame 3 is lowered by its own weight. As a result, the claw-shaped shell 2 is moved in the opening direction, and the grab 1 is opened and the held cargo falls.

  The lowering of the lower frame 3 is regulated by a stopper 52 provided on the guide shaft 50, and the impact at the time of stopping is buffered by a spring 53.

  The above-described conventional polyp type single rope type grab bucket is designed so that the intermediate movable frame 7 comes into contact with the upper frame 5 when the grab 1 is completely closed. When the opening operation is performed from the closed state, a smooth opening operation is performed.

  However, if the cargo to be grabbed is difficult to grasp such as scrap, large block ore, rock, sticky material, bulky trash, wood chips, etc., in most cases the grab 1 will not be completely closed, The opening operation is performed from the state. As shown in FIG. 8, when the grab 1 is not completely closed, that is, when a gap L is formed between the opposing claw-shaped shells 2 and 2, a gap t is generated between the upper frame 5 and the intermediate movable frame 7. In addition, the upper frame 5 and the intermediate movable frame 7 are in a state of being loaded with a large load in the approaching direction by the wire rope 8.

  When the opening / closing claw 51 is opened from this state and the lower frame 3 is separated from the intermediate movable frame 7, the intermediate movable frame 7 instantaneously removes the downward load due to the weight of the cargo. The gap between the frame 5 and the frame 5 is instantaneously moved toward the upper frame 5 and violently collides with the upper frame 5 to generate a large impact with a large impact sound. This impact is transmitted and the crane vibrates greatly. This impact increases as the capacity of the bucket increases, and the impact applied to the crane and other cargo handling machines at the time of occurrence is about 1.5 times the total weight of the bucket and the cargo, which is very dangerous. was there.

  In order to avoid such a danger, when carrying out the cargo handling operation with the cargo sandwiched between the claw-shaped shells 2, 2,..., The grab 1 is grounded to the open position, and the upper frame 5 and the intermediate movable frame 7 are contacted. It is necessary to open the grab 1 after avoiding a collision between the two and the work efficiency is poor.

    The present invention has been made in view of the state of the prior art as described above, and is intended to provide a polyp type single-line grab bucket that can safely and efficiently perform cargo handling work even when cargo is sandwiched between claws. It is a thing.

In order to solve the conventional problems as described above and achieve the intended purpose, the invention is characterized in that an upper frame, an intermediate movable frame and a lower frame are provided in the vertical direction, and the lower portion is provided. An upper end side of the claw-shaped shell is rotatably supported with a horizontal support shaft in a radial arrangement with respect to the frame, and includes a suspension arm that connects the back surface of each claw-shaped shell and the upper frame, Between the movable frame and the upper frame, a bucket lifting operation wire is wound around a pulley provided for each, and is moved in a direction approaching each other by a lifting operation by the wire, and between the intermediate movable frame and the lower frame, A polyp type single-line grab bucket equipped with a middle-lower frame relative motion control mechanism that regulates and cancels the relative motion between both frames. Stomach,
The middle-lower frame relative movement restricting means includes a hydraulic cylinder that regulates the relative movement in the vertical direction between the intermediate movable frame and the lower frame, and a hydraulic cylinder control means that controls the operation of the hydraulic cylinder,
The hydraulic cylinder control means has in parallel a flow restricting valve mechanism capable of circulating only a small amount of hydraulic oil and a normal operation valve mechanism capable of circulating a large amount of hydraulic oil, separated by a piston of the hydraulic cylinder. A hydraulic passage that communicates between the upper and lower hydraulic chambers, and a hydraulic sensor that detects the hydraulic pressure of the hydraulic passage,
If the pressure in the hydraulic flow path is greater than or equal to a predetermined value during the claw-shaped shell opening operation, only a small amount of hydraulic oil is circulated through the flow restricting valve mechanism. That is, hydraulic oil is circulated through the valve mechanism for operation.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, the flow restricting valve mechanism includes a valve body biased in a direction to close the hydraulic flow path, and a closing direction of the valve body. And a logic valve that circulates only a small amount of hydraulic oil having a spring chamber that communicates with the hydraulic circuit via a solenoid valve, and energizes the solenoid valve to drain the spring chamber. By opening, the valve body is biased in the direction to open the hydraulic flow path against the spring.

  Furthermore, the invention according to claim 3 is characterized in that, in addition to the configuration of claim 1 or 2, the normal operation valve mechanism includes a valve body biased in a direction to close the hydraulic flow path, and the valve body. A logic valve having a spring that is energized in the closing direction and having a spring chamber that communicates with the hydraulic flow path via a solenoid valve is provided, and the solenoid valve energizes the solenoid valve by detecting a predetermined pressure. The valve chamber is biased in the direction to open the hydraulic circuit against the spring by opening the drain of the spring chamber by the energization.

The polyp type single rope type grab bucket according to the present invention as described above,
An upper frame, an intermediate movable frame, and a lower frame are provided in the vertical direction, and the upper end side of the claw-shaped shell is rotatably supported by a horizontal support shaft in a radial arrangement with respect to the lower frame. A suspension arm connecting the back surface of the claw-shaped shell and the upper frame is provided, and a bucket suspension operation wire is wound around a pulley provided between each of the intermediate movable frame and the upper frame. A polyp type single rope type which is operated in the approaching direction, and is provided with a middle-lower frame relative motion control mechanism for regulating and releasing the relative motion between the middle movable frame and the lower frame. In the grab bucket, the relative movement restricting means between the middle and lower frames includes the upper frame between the intermediate movable frame and the lower frame. By using a hydraulic cylinder that regulates the relative movement in the direction and a hydraulic cylinder control means that controls the operation of the hydraulic cylinder, the impact generated when the cargo handling operation is performed in a state where the claw-shaped shell is not completely closed is hydraulically It can be structured to be absorbed by the mechanism.

  The hydraulic cylinder control means has a flow rate limiting valve mechanism capable of circulating only a small amount of hydraulic oil and a normal operation valve mechanism capable of distributing a large amount of hydraulic oil in parallel. A hydraulic passage that communicates between the separated upper and lower hydraulic chambers, and a hydraulic sensor that detects the hydraulic pressure of the hydraulic passage, and the pressure of the hydraulic passage is greater than or equal to a predetermined value during the claw-shaped shell opening operation. For example, the claw-type shell is configured such that only a small amount of hydraulic oil is circulated through the flow restricting valve mechanism and the hydraulic oil is circulated through the normal operation valve mechanism if the hydraulic circuit has a pressure equal to or lower than a predetermined value. When cargo handling work such as lump ore is sandwiched between them, the impact between the upper frame and the intermediate movable frame can be relieved even if the grab is opened while suspended. It can be carried out safely and efficiently loading and unloading.

  Further, the flow restricting valve mechanism is provided with a valve body biased in the closing direction of the hydraulic flow path and a spring for biasing the valve body in the closing direction, and communicated with the hydraulic circuit via an electromagnetic valve. And a logic valve that circulates only a small amount of hydraulic oil having a spring chamber, and by energizing the solenoid valve to open the drain of the spring chamber, the valve body resists the spring through the hydraulic flow path. By being biased in the opening direction, the flow restricting valve mechanism can be suitably controlled.

  Furthermore, the valve mechanism for normal operation is provided with a valve body biased in the closing direction of the hydraulic flow path and a spring for biasing the valve body in the closing direction, and the hydraulic flow through the electromagnetic valve. A logic valve having a spring chamber in communication with the passage, and a pressure sensor detects a predetermined pressure to energize the solenoid valve, and the energization opens the drain of the spring chamber to resist the spring. By switching the valve body in the direction to open the hydraulic circuit, it is possible to suitably control the operation switching between the flow rate limiting valve mechanism and the normal operation valve mechanism.

  As described above, the polyp type single rope type grab bucket according to the present invention can perform the work safely and efficiently even when the cargo handling work is performed with the cargo sandwiched between the claws.

  Next, embodiments of the present invention will be described based on examples shown in the drawings.

  1 to 5 show an example of a polyp type single rope type grab bucket according to the present invention. This grab bucket constitutes a grab 1 and has six claw-shaped shells 2 opened and closed facing each other. 2 ..., a lower frame 3 in which the center of rotation of each claw-shaped shell 2 is pivotally supported by a horizontal axis 2a, and the upper surface of the lower frame 3, the back surface of each claw-shaped shell 2 and a suspension arm 4 is connected to the upper frame 5 via the hydraulic frame 6 between the upper frame 5 and the lower and upper frames, and the lower end is fixed to the intermediate movable frame 7. In addition, a wire rope 8 for hanging and grab closing wound around pulleys provided on the intermediate movable frame 7 and the upper frame 5 and extending upward, and an oil flow leading into the hydraulic cylinder 6 It is constituted by a hydraulic cylinder control means for controlling the operation of the hydraulic cylinder 6 by opening and closing.

  The grab 1 is composed of claw-shaped shells 2, 2... That are pivotally supported by a shaft 2a with respect to the lower frame 3, and the closed state in which the side edges of the claw-shaped shells 2 are joined to each other. At this time, the bottom portion is closed and a gripping space 9 is formed in which cargo such as loose articles is accommodated. From the closed state, the claw-shaped shells 2, 2,. It is comprised so that it can open | release in the shape of a petal radially arranged in the circumference | surroundings.

  Further, the lower end portion of the suspension arm 4 is pivotally supported on the back portion of each claw-type shell 2, and the upper end portion of the suspension arm 4 is pivotally supported on the upper frame 5. It is connected to the upper frame 5 in a suspended state.

  An oil tank 11 and a radio signal receiver 12 are attached to the lower frame 3. Note that reference numeral 14 in the figure denotes a receiving antenna of the radio signal receiver.

  The hydraulic cylinder 6 includes a cylinder part 6a, a piston 6b accommodated in the cylinder part 6a so as to be reciprocally movable, and a piston rod 6c connected to the piston 6b and projecting freely from the upper end of the cylinder part 6a. It is configured.

  The lower end of the cylinder portion 6a is connected to the lower frame 3 and the tip of the piston rod 6b is connected to the top of the intermediate movable frame 7 by screwing or the like, whereby the lower frame 3 and the intermediate movable frame 7 are connected to the hydraulic cylinder. 6 are connected. Further, the piston 6b is provided with a rod-shaped piston rod 6c protruding upward.

  When receiving a signal from the wireless signal transmitter, the wireless signal receiver 12 transmits a release command to the hydraulic circuit that controls the hydraulic cylinder 6.

  The upper frame 5 is formed in a shape in which the upper portion of the intermediate movable frame 7 is fitted in the central portion thereof, and includes rotatable pulleys 18 and 18 at the front and rear portions.

  The intermediate movable frame 7 is formed in a shape having a hollow portion inside, and sheave cases 16 and 16 are fixedly provided on the lower right side of the front surface and the lower left side of the rear surface, and pulleys 17 and 17 are provided in the sheave cases 16 and 16. Is rotatably provided.

  The intermediate movable frame 7 is suspended relative to the upper frame 5 by the operation of the wire rope 8. That is, as shown in FIG. 5, the lower end of the wire rope 8 is fixed to both sides of the intermediate movable frame 7, and the wire rope 8 is wound around pulleys 17 and 17 via pulleys 18 and 18 of the upper frame 5, respectively. The upper end of the hook is extended upward and the upper end is fixed to a hanging tool 19 for hanging it on a crane or the like.

  When opening the grab 1, as shown in FIG. 1, the hydraulic cylinder control means is operated to bring the hydraulic cylinder 6 into a free state, so that the lower frame 3 has its own weight of the claw shell and the lower frame 3. Accordingly, it is separated from the intermediate movable frame 7 and descends, and the position of the rotation center shaft 2a is lowered while the back surface of the claw-shaped shell 2 is suspended by the suspension arm 4, so that the grab is opened.

  Further, as shown in FIG. 4, the operation of the grab 1 in the closing direction is to lower the intermediate movable frame 7 by extending the wire rope 8 from the open state in the direction in which the hydraulic cylinder 6 is left free. To approach the lower frame 3. In this state, the hydraulic cylinder 6 is made unextendable, and the wire rope 8 is pulled up as shown in FIG. 3, so that the intermediate movable frame 7 is pulled up so as to approach the upper frame 5, thereby the two-claw shells 2, 2. Are operated in directions to close each other.

  The hydraulic cylinder control means for controlling the operation of the hydraulic cylinder 6 is constituted by a hydraulic circuit as shown in FIG.

  The hydraulic circuit includes a hydraulic flow path 30 that communicates between upper and lower hydraulic chambers separated by a piston 6 b of the hydraulic cylinder 6, and a hydraulic sensor 31 that detects the hydraulic pressure of the hydraulic flow path. The lower end portion communicates with the oil tank 11 through the connection conduit 32.

  The hydraulic flow path 30 includes a flow restriction valve mechanism capable of circulating only a small amount of hydraulic oil and a normal operation valve mechanism capable of circulating a large amount of hydraulic oil in parallel. If the oil pressure in the hydraulic passage is greater than or equal to a predetermined value, only a small amount of hydraulic oil is circulated through the valve mechanism for restricting the flow rate. It is supposed to let you.

  The flow restricting valve mechanism is a logic valve having a poppet valve body 33 biased in a closing direction of the hydraulic flow path 30 and a spring chamber 35 in which a spring 34 for biasing the valve body 33 in the closing direction is installed. 36, the conduit connected to the upper end of the cylinder portion 6a of the hydraulic cylinder 6 is branched in the middle, and one flow path 30a is communicated with the spring chamber 35 of the logic valve 36 via the throttle valve 37 and the electromagnetic valve 38, and the other The flow path 30b is connected to the lower end portion of the cylinder portion 6a through an open / close chamber 39 that is opened and closed by the poppet valve body 33 of the logic valve 36.

  The spring chamber 35 of the logic valve is connected to the drain DR by switching the electromagnetic valve 38, that is, by energizing the electromagnetic valve 38, so that the drain is opened.

  The logic valve 36 is formed so that the pressure receiving area on the opening / closing chamber inlet side of the poppet valve body 33 is smaller than the pressure receiving area on the spring chamber side, so that when the electromagnetic valve 38 is not energized, that is, in the hydraulic flow path 30. When connected, the poppet valve body 33 is pressed in the direction of closing the hydraulic flow path 30 by the fluid pressure due to the difference in pressure receiving area and the elastic force of the spring.

  However, when the solenoid valve 38 is switched by energization and the spring chamber 35 is connected to the drain DR, the hydraulic pressure in the spring chamber 35 decreases, and the hydraulic pressure of the hydraulic flow path to the opening / closing chamber inlet side of the poppet valve body 33 is reduced. In response to this, the poppet valve body 33 is biased in the direction of opening the hydraulic flow path 30 against the elastic force of the spring 34, so that the hydraulic oil flows through the hydraulic flow path 30.

  The open / close chamber outlet portion 39a of the logic valve 36 is formed in a constricted shape so that only a small amount of hydraulic oil flows.

  The electromagnetic valve 38 is caused to receive a grab opening signal by the radio signal receiver 12 so that an operating current flows, and the electromagnetic valve 38 is switched to the side connecting the spring chamber 35 to the drain DR only during the energization. It is like that.

  The normal operation valve mechanism is a logic valve having a poppet valve body 40 biased in a closing direction of the hydraulic flow path 30 and a spring chamber 42 in which a spring 41 for biasing the valve body 40 in the closing direction is installed. 43, a conduit connected to the upper end of the cylinder part 6a of the hydraulic cylinder 6 is branched in the middle, and one flow path 30c communicates with the spring chamber 42 of the logic valve 43 via the throttle valve 44 and the electromagnetic valve 45, and the other This flow path is connected to the lower end portion of the cylinder portion 6a through an open / close chamber 46 opened and closed by the poppet valve body 40 of the logic valve 43.

  The spring chamber 42 of the logic valve 43 is connected to the drain DR by switching the electromagnetic valve 45, that is, by energizing the electromagnetic valve 45, and the drain is opened.

  The logic valve 43 is formed so that the pressure receiving area on the opening / closing chamber inlet side of the poppet valve body 40 is smaller than the pressure receiving area on the spring chamber side, so that the solenoid valve 45 is not energized, that is, the spring chamber 42 is hydraulic. When connected to the flow path 30, the poppet valve body 40 is pressed in a direction to close the hydraulic flow path 30 by the fluid pressure due to the difference in pressure receiving area and the elastic force of the spring 41.

  However, when the solenoid valve 45 is energized to switch the flow path and the spring chamber 42 is connected to the drain DR, the hydraulic pressure in the spring chamber 42 decreases, and the hydraulic pressure flows to the opening / closing chamber inlet side of the poppet valve body 40. In response to the hydraulic pressure of the passage 30, the poppet valve body 40 is biased in a direction to open the hydraulic passage 30 against the elastic force of the spring 41, and the hydraulic oil is circulated through the hydraulic passage.

  A pressure sensor 31 is connected to the electromagnetic valve 45, and energization is performed only when the pressure sensor 31 detects a hydraulic pressure equal to or lower than a predetermined value. Therefore, the logic valve 43 is opened only when the hydraulic pressure in the hydraulic flow path 30 is equal to or less than a predetermined value, and hydraulic oil is circulated in the hydraulic flow path 30.

  Next, the opening operation in a state where the cargo a is sandwiched between the two claws-type shells 2 and 2 of the grab bucket will be described.

  As shown in FIG. 3, when the grab bucket performs a cargo handling operation while holding a cargo a such as a lump ore between the claws 2 and 2, between the upper frame 5 and the intermediate movable frame 7, A gap t is created according to the size of the sandwiched object.

  At this time, the solenoid valves 38 and 45 of the hydraulic circuit are not energized, and the solenoid valves 38 and 45 are in a state in which the spring chambers 35 and 42 of the logic valves 36 and 43 and the hydraulic flow path 30 communicate with each other. Since both the logic valves 36 and 43 urge the poppet valve bodies 33 and 40 in the direction of closing the hydraulic flow path 30 by the springs 34 and 41 and the hydraulic pressure, the oil flow in the hydraulic cylinder 6 is The hydraulic cylinder 6 is locked.

  In order to open the grab 1, first, the radio signal receiver 12 receives a grab opening signal to energize the solenoid valve (solenoid valve) 38, and the solenoid valve 38 is drained only during the energization. The state is switched to a state where the DR and the spring chamber 35 are in communication with each other, and the spring chamber 35 of the logic valve 36 is drained.

  When the drain is opened, the hydraulic pressure acting on the opening / closing chamber side of the valve body 33 becomes larger than the elastic force of the spring 34, the poppet valve body 33 is biased upward against the spring 34, and the logic valve 36 is opened. A small amount of hydraulic oil flows between the upper and lower hydraulic chambers of the hydraulic cylinder 6, and the hydraulic cylinder 6 starts to move in the extending direction.

  At this time, since a gap t is generated between the upper frame 5 and the intermediate movable frame 7 in the hydraulic cylinder 6, a pressure about three times the weight of the bucket acts. By allowing only a small amount of hydraulic oil to circulate, a damper effect is obtained, and the gap t between the upper frame 5 and the intermediate movable frame 7 is slowly narrowed, and the upper frame 5 and the intermediate movable frame 7 can be moved with little impact. And the claw-shaped shells 2 and 2 move slowly in the opening direction as the hydraulic cylinder 6 extends.

  When the upper frame 5 and the intermediate movable frame 7 come into contact with each other, only the bucket weight acts on the hydraulic cylinder 6, and the hydraulic pressure in the hydraulic cylinder 6 is 1/3 of the bucket opening operation, that is, the hydraulic pressure during normal operation. The hydraulic pressure sensor 31 detects the pressure and energizes the electromagnetic valve 45.

  As a result, the electromagnetic valve 45 is operated in a state where the drain DR and the spring chamber 42 are in communication, and the spring chamber 42 is drained.

  When the drain is released, the hydraulic pressure in the spring chamber 42 decreases, the hydraulic pressure applied to the opening / closing chamber side of the valve body 40 becomes larger than the elastic force of the spring 41, and the valve body 40 is attached upward against the spring 41. As a result, the logic valve 43 is opened, the hydraulic oil is circulated through the hydraulic passage 30, and the hydraulic cylinder 6 is completely free.

  As a result, the lower frame 3 is detached from the intermediate movable frame 7 by the weight of the claw-shaped shells 2 and 2 and the lower frame 3 and descends, and the crotch-shaped shell 2 is suspended by the suspension arm 4 and the central axis 2a is turned. The position is lowered and the grab 1 is opened.

  In the above-described embodiment, an example in which the electromagnetic valve is opened and closed by a wireless operating device has been shown, but a wired type may be used. Moreover, although the case where 6 nail | claw type | mold shells are used is shown, 4 or 8 may be used as appropriate.

It is a longitudinal cross-sectional view which shows the grab open state of an example of the polyp type single rope type grab bucket which concerns on this invention. It is a top view of the grab obstruction | occlusion state same as the above. It is a longitudinal cross-sectional view which shows the state which pinched | interposed and grasped cargo between the same nail | claw-shaped shells. It is a longitudinal cross-sectional view which shows the grab open state of the polyp type single rope type grab bucket shown in FIG. It is a perspective view which shows the winding state of the pulley and wire rope which are used for the polyp type single rope type grab bucket shown in FIG. It is a hydraulic circuit diagram of the hydraulic cylinder control means used for the polyp type single rope type grab bucket shown in FIG. It is a longitudinal cross-sectional view which shows the open state of the conventional polyp type single rope type grab bucket. It is a longitudinal cross-sectional view which shows the case where it lifts in the state which pinched | interposed cargo between the same nail | claw type | mold shells.

Explanation of symbols

a Cargo 1 Grab 2 Claw-shaped shell 3 Lower frame 4 Lifting arm 5 Upper frame 6 Hydraulic cylinder 6a Cylinder part 6b Piston 6c Piston rod 7 Intermediate movable frame 8 Wire rope 9 Grasp space 11 Oil tank 12 Radio signal receiver 14 Antenna 16 Sheave Case 17 Pulley 18 Pulley 19 Lifting tool 30 Hydraulic flow path 31 Hydraulic sensor 32 Connection conduit 33 Poppet valve body 34 Spring 35 Spring chamber 36 Logic valve 37 Throttle valve 38 Electromagnetic valve 39 Open / close chamber 40 Poppet valve body 41 Spring 42 Spring chamber 43 Logic Valve 44 Throttle valve 45 Solenoid valve 46 Opening / closing chamber DR Drain

Claims (3)

An upper frame, an intermediate movable frame, and a lower frame are provided in the vertical direction, and the upper end side of the claw-shaped shell is rotatably supported by a horizontal support shaft in a radial arrangement with respect to the lower frame. A suspension arm connecting the back surface of the claw-shaped shell and the upper frame is provided, and a bucket suspension operation wire is wound around a pulley provided between each of the intermediate movable frame and the upper frame. A polyp type single rope type which is operated in the approaching direction, and is provided with a middle-lower frame relative motion control mechanism for regulating and releasing the relative motion between the middle movable frame and the lower frame. In grab bucket,
The middle-lower frame relative movement restricting means includes a hydraulic cylinder that regulates the relative movement in the vertical direction between the intermediate movable frame and the lower frame, and a hydraulic cylinder control means that controls the operation of the hydraulic cylinder,
The hydraulic cylinder control means has in parallel a flow rate limiting valve mechanism capable of circulating only a small amount of hydraulic oil and a normal operation valve mechanism capable of circulating a large amount of hydraulic oil, separated by a piston of the hydraulic cylinder. A hydraulic passage that communicates between the upper and lower hydraulic chambers, and a hydraulic sensor that detects the hydraulic pressure of the hydraulic passage,
When the claw-type shell is opened, if the pressure in the hydraulic flow path is equal to or higher than a predetermined value, only a small amount of hydraulic oil is circulated through the flow restricting valve mechanism. A polyp type single rope type grab bucket characterized in that hydraulic oil is circulated through a valve mechanism for operation.   The valve mechanism for restricting the flow rate is provided with a valve body that is biased in the closing direction of the hydraulic flow path, and a spring that biases the valve body in the closing direction and communicated with the hydraulic circuit via an electromagnetic valve. A valve that opens the hydraulic flow path against the spring by energizing the solenoid valve and opening the drain of the spring chamber. The polyp type single rope type grab bucket according to claim 1, wherein the polyp type single rope type grab bucket is urged to be applied.   The valve mechanism for normal operation is provided with a valve body biased in the closing direction of the hydraulic flow path and a spring for biasing the valve body in the closing direction and communicated with the hydraulic flow path through an electromagnetic valve. A logic valve having a spring chamber, and when a pressure sensor detects a predetermined pressure, the solenoid valve is energized, and the energization opens the drain of the spring chamber so that the valve body resists the spring. The polyp type single rope type grab bucket according to claim 1 or 2, wherein the hydraulic circuit is biased in a direction of opening.

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